Symptom: application opens /dev/ttyGS0 and starts sending (writing) toit while either USB cable is not connected, or nobody listens on theother side of the cable. If driver circular buffer overflows beforeconnection is established, no data will be written to the USB layeruntil/unless /dev/ttyGS0 is closed and re-opened again by theapplication (the latter besides having no means of being notified aboutthe event of establishing of the connection.)